Automatic potential-control system



2 Sheets-Sheet 1 H. ARKUS AUTOMATIC POTENTIAL CONTROL SYSTEM April 13, 1954 Filed sept. 1s, 1951 ATTORNEY April 13, 1954 H. ARKUs 2,675,472

AUTOMATIC POTENTIAL-CONTROL SYSTEM Filed Sept. 13, 1951 2 Sheets-Sheet 2 O O l lvuuawd wnuawd I mwawd lpnuawd INVENTOR. HENRY ARKUS ATTO R NEY Patented Apr. 13, 1954 UNITED STATES PATENT OFFICE AUTOMATIC POTENTIAL-CONTROL SYSTEM Henry Arkus, Brooklyn, N. Y., assignor to Hazeltine Researchlnc., Chicago, Ill., a. corporation of Illinois Application September 13, 1951, Serial No. 246,413

12 Claims. (Cl. Z50- 27) l 2 General gated system atv a predetermined valueY during The present invention relates to automatic potential-control systems vand,'morev particularly, to such control systems of the type which automatically maintains the potential at a point in the system at a predetermined value during given intervals. Such a control system has particular utility in a radar system and, hence, will be described in that environment.

Heretofore, so-called clamp circuits have commonly Vbeenv utilized to maintain the potential at a point in a ,circuit at a predetermined value despite tendencies vof the potential to vary positively or negatively. Such clamp circuits, when utilizing tubesV of moder.ate'sizehave had output impedances of the order of afew hundred ohms.

To p -rovide lower outputimpedances-for these circuits, it has been proposed to utilize larger tubes having heavier current-'carrying capacities. However, becausek such tubes are noty readily disabledr and require. sources of `-largevamounts of powenthe. proposed circuits are not satisfactory for some radar applications requiring, for example, a gated potential-control system for controlling during given intervals the potential at a point in a sweep amplifier 'of a radar system utilizing a gated lsweep generator and for isolat ing that pointfrom alsourceoi potential during other intervals to stabilize the operation of' the sweep amplifier.

Itis anvobject ofthe presentinvention, therefore, to-provide a new and improved automatic potential-control system which avoids one or more of the above-mentioned disadvantages and limitations voi systems` heretofore proposed.

Itis another object of the invention toprovide new andimproved control. system. forv automatically maintaining the potential' at apoint in the system at a predetermined value during given intervals and for isolating that point fromasource of potential during other intervals.

it is still another object of the invention to provide. for use in a radar system a new and improved control system for automatically maintaining the potential at a point in the radar sys-` tem at a predetermined-value during given intervals by means of which the operation of a sweep amplifier of the radar system may be stab"- lized.

In accordance with a particular form of the invention, in a gated system having one operating phaseduring predetermined gating intervals and another operating phase during the intervening intervals. a control system `for automatically maintaining the potential-at a given point in the the intervening intervals comprises a signal-responsive potential-supply circuit having a controlla-ble potential-current ow characteristic and signal-responsive circuit means coupled in circuit with the aforesaid supply circuit and the given point. The control system also includes a circuit for supplying to the aforesaid circuit means repetitive gating pulses for rendering Ythe same nonconductive and meansv including said signal-responsive circuit means for isolating the given point from the* potential-supply circuit Within the control system during the gating intervals. The control system further includes a circuit coupled to thegiven point andthe aforesaid potential-supply circuit and' .responsive to deviations of the potential; atY the givenpoint from the aforesaidy predetermined value during the intervening intervalsfor applying tothe potential-supply circuit a. control signal' variable in magnitude during the intervening intervals and determined lduring the'intervening intervals by the potentialat the given point'iorxcontrolling the aforesaid characteristic of the'potential-supply circuit tomaintain the potential at the given point at the predetermined value during the intervening intervals.

Also in .accordance with a particular'form vof tire invention, in a gated system having one operating phase during predetermined gating intervals and another operating phase during the vintervening intervals, a control system for autolrnatically maintaining the potential at a given point in the gated system at a predetermined value during the intervening intervals comprises a potential-supply circuitand a two-partfvoltage divider coupled in aseries relation/With the potential-supply circuit. One part includes potential-responsive iirst circuit means 4ofvariable, impedance for controlling' current now therethrough Vand the other part includes a second circuit means of substantial impedance. The' control system includes potential-responsive third circuit means coupled between the potential-supply f circuit and the aforesaid given point. The control system also includes a circuit for applying to the aforesaid third circuit means repetitive gating potential pulses for rendering the same ncnconductive and means. including theV aforesaid third circuit means fcr isolating thef given point from the supply circuit within the control system during the gating intervals. The control system also includes a circuity coupledbetween the given point and the-*rstf circuit means and responsive to deviations 'of `thepotential at the given point from the aforesaid predetermined value during the intervening intervals for applying to the rst circuit means a control potential variable in magnitude during the intervening intervals and determined during the intervening intervals by the potential at the given point for controlling the impedance of the rst circuit means to maintain the potential at the given point at the predetermined value during the intervening intervals.

For a better understanding of the present invention, together With other and further objects thereof, reference is had to the following description taken in connection with the accompanying drawings, and its scope will be pointed out in the appended claims.

In the accompanying drawings, Fig. 1 is a schematic circuit diagram of a radar system including an automatic potential-control system constructed in accordance with a particular form of the invention; and Fig. 2 is a graph representing the potential-time characteristics of the output signals of various units of the Fig. 1 radar system to aid in explaining the invention.

General description of Fig. 1 radar system Referring now more particularly to Fig. l, there is represented a gated radar system having one operating phase during predetermined gating intervals and another operating phase during the intervening intervals including an automatic potential-control system in accordance with the invention. The radar system comprises the .usual synchronizing circuits III which may include a suitable repetition rate oscillator and pulse generator circuits well known in the art. The synchronizing circuits II) are coupled through a modulator il of conventional construction to a transmitter I2 for transmitting pulse-modulated radar signals. The transmitter I2 is coupled in a usual manner to an antenna I4 through a duplexer I3 which may be of any suitable type, such as one described in Chapter XI o-f the text Principies of Radar, second edition, by the Massachusetts Institute of Technology Radar School Staff, McGraw-Hill, 1946. The antenna I4 is also coupled through the duplexer I3 to a receiver I5 of conventional construction for receiving and detecting echo signals intercepted by the antenna I4 and for applying with amplification the video-frequency modulation components of these signals to an input circuit of a plan-position indicator I6 which may comprise a cathode-ray tube of a well-known type.

The radar system also includes a gating pulse generator system I1 coupled to an output circuit of the modulator II for generating gating pulses in response to trigger pulses applied thereto by the modulator. The gating pulse generator system il' may be similar to that disclosed and claimed in the copending application Serial No. 246,456 of Jasper J. Okrent, entitled Control System for Automatically Varying the Duration of Repetitive Pulses, and filed September 13, 1951. An output circuit of the gating pulse generator system I1 is coupled to a sweep generator I3 for generating saw-tooth pulses during the intervals of the gating pulses applied thereto. This output circuit of the unit I1 is also coupled to the cathode-ray tube of the indicator IS for rendering that tube conductive during the sweep time of the output signal of the sweep generator I8. Another output circuit of the unit I1 is coupled to an automatic potential-control system 22 constructed in accordance with the invention and more fully described hereinafter and to an automatic potential-control system 2E simllar to the unit 22.

The output circuit of the sweep generator I3 is coupled to the rotor winding I9a of a conventional signal resolver, such as a synchro I, having two stator windings Ib and I9c displaced 90 from each other for resolving the output signal of the sweep generator l,I8 into two components having amplitudes which individually vary in accordance with the sine and cosine of the angle of the rotor winding I9a relative to a predetermined reference. The rotor winding I9a ordinarily is positioned in accordance with the position of the antenna I4 by any suitable means (not shown). The winding I9b is coupled to the input circuit of a suitable sweep amplifier 2B of one or more stages, which is, in turn, coupled to a sweep amplifier 23 through a coupling condenser 2l and the control system 22. The output circuit of the sweep amplifier 23 is coupled to a deiiection circuit of the plan-position indicator I6 for supplying one component of a sweep signal to that indicator.

The stator winding I9c of the synchro I9 is coupled in a similar manner through a sweep amplifier 24, .a condenser 25, the automatic potential-control system 26, `constructed in accordance with the invention, and a sweep amplifier 21 to another deflection circuit of the plan-position indicator IB for supplying another component of the sweep signal to that indicator.

Units 24, 26, 21 and the coupling condenser 25 preferably are of construction similar to that r of units 20, 22, 23 and the coupling condenser 2 I,

respectively. Units III-I3, inclusive, I5, I6, I8-20, inclusive, 23, 24, 21 and the antenna I4 may all be of conventional construction and operation so that a detailed explanation of the operation thereof is deemed unnecessary.

General operation, of Fig. 1 radar system Considering briey, however, the operation of the Fig. 1 radar system as a whole, the synchronizing circuits I0 periodically apply to the modulator II trigger pulses having a repetition frequency determined by the frequency of the repetition rate oscillator of the unit I0. For convenience, the arrows represent the direction of signal propagation. The trigger pulses from the unit I0 periodically re the modulator II, which, in turn, pulse-modulates the output signal of the transmitter I2 and causes the transmitter to apply to the antenna I4 through the duplexer I 3 periodic bursts of high-frequency wave-signal energy. During the operation of the transmitter I2, the duplexer I3 protects the receiver I5 from being overloaded by the transmitted pulses. During the intervals between transmitted pulses, the receiver I5 responds to any echo signals intercepted by the antenna I4, detects the modulation components of these signals and applies the detected signals to the plan-position indicator I6.

Output pulses of the modulator II are also applied to the gating pulse generator system I1. In response to these pulses, the gating pulse generator system I1 applies repetitive gating pulses to the sweep generator I8. During the intervals of these gating pulses, the sweep generator I8 develops saw-tooth pulses which are applied as a sweep signal to the rotor winding |911 of the .synchro I9. Gating pulses are also applied by the gating' pulse generator system I1 to the unit I6 to render conductive the cathode-ray tube of ithatzzunitrduring.'.therrsiveepztime .of-:.theenntput rsignal: ofthefsweep 'zgenerator '1.8.

:The synchro i i9v iresolves the :signal :applied to .'therotor winding .I 91a, into two :components having :amplitudes which individually iva-'ry in :ac-

cordancewith the sine and .cosine iof: the .angle y of Ithe `rotor winding .zl Safrelativetoa vpredeter- `mined reference.

.The component-of the .sweep signal developed across the stator winding :19h

`is .amplied..by:; the sweep :amplifier 2!) vandf ap- "plied through .the coupling condenser 2 |,x the vother deectioncircuit of thegplan-positionpin- `dicator i5. .The components of the-sweepv signal applied to the deection circuits` of thexplanposition indicator i6 deect the cathode-ray ,beamof .the indicator .i6 in a-,usual mannergto develop onthe screenthereof a plan view ofthe area :being scanned by the radar. apparatus.

` Description of Fzgnil automatic potentialcontrol system vReferringwnovv more'particularly to the unit 22xof the Fig. l radar system, that unit corn- .prises a: control system 'for automatically maintaining-'the potential atfa given point 26 inthe .radar-:system..at a 4predetermined value,`for example, zero potential, during-the intervals inter- I vening the gating intervals vestablished by the .fgatingpulse generator system I1.

The control system Ycomprises a 'potential-supply circuit,

namely, asourcefof unidirectional potential having a negative terminal- 'Bfanda .positivevterminal -l-B. 'The .potential-control 'system also includes atWo-part voltagediv-ider coupled kin a series relation with the potential-supplycircuit and preferably. having 'the above-.mentioned given pointlz intermediate the two parts. part of the voltage dividerincludes.potential- 4responsive rst circuit means of variable impedance ifor controlling current flow .therethrough. ,More lparticularly, the potential-'responsive circuit means. comprises a first electrondischarge device. of' Variable impedance, namely, a :tube 2.9 for .controlling :currentjflow through the-mst voltage-dividerpart. The anodel ofthe tube 29 is directly connected :tothe source-kB, While the control'electrode of the tube`29 iscoupled through a .resistor 3! for .suppressing parasitic oscillations to a :point on. a voltage div vider .comprising :airesistor '32, 'ai resistor 33: and .a parallel-connected; Ahigh-.frequency lbit-'pass condenser 34, and `aresistcrxfii coupled' in aseries relation Vbetween a .source 'B" and the source -l-B. .Theca-thode ofthe tubelsisrcoupled to a second electron-discharge device, `specificallya `diode 36, includedinineansrto'be described subsequently and coupledxbetween the .source-+B and the givenfpoint in a series'relation with therstelectron-discharge.device29 and with a predetermined polarity for completely interrupting current flow through the first voltagedividerpart. Thejunction ofthe cathode of the tube29 and the anode ofthe diodel35 is coupled through a resistors? to the source -B.

The otherpart of the vcltagedividerin'cludes .a second circuit `means-oi? substantialimpedance. .A potential-responsive.thirdicircuitmeans is cou- One its

pled '.between .the potential-supply;rcircuit rand the givenipoint. Moreparticularly;this-potential-responsive vthirdfcircuitl meansv includes a unidirectionally `conductive'device;specifically,. a diode 33 which is coupledbetween:theisource-B and the givenpoint.28vzith:thesameipolarity as the diode '36 is ycoupled between .the-givenypoint 23 and the source +B. The above-mentioned second .circuit :means comprises an" ,element i of substantial impedance, namely, fa' resistor 39 series-connected between the cathode .of thediode 33 and the source -B.

The .potential-supply circuit may. also vbe considered' to comprise the. source +B, -B, the tube 29, and the resistor A`39 'and in such case the potential-supply circuit has a fcontrollablepotential-'current' flow vcharacteristic. The `potentialcontrol systern'further-includes a gatingcircuit for` applying to vthe :above-mentioned potential- 'responsive third :circuit means v:repetitive poten- Atial pulses'for rendering .the samenonconductive.

Means including J .the aforesaid :thirdf acircut means also is'provided ".or isolating ..thefagiven -B during the -gatng'rintervals This means also includesdiode'. .'.["he;gating :circuitrincludes a tuber40 havinga control electrode-'coupled through ai current-limiting. `resistorfdl l: totthe output circuit of the 'gating .pulse generator :sys-

tem I1. Thecathode of thettube' 40is `connected to a condenser 43'and is coupled through-.'acathode'` resistor i2 and the.resistor"39'to the .source --B. The anode'of the tubed is directlypon- The gatingcircuit also; includes "a tube "44'- having a controlelectrode coupled .through `a current-limiting resistorto the output vcircuit 'of the gating.pulsergeneratorV system I1. The cathode of the tube 'lidiy is rcoupled through a cathode resistor i6 to the source 'B Va'nd'the'anode thereof is directly connectedito the source/+B. "The vrgating circuitfurther includes a-tube-"lilhaving a control `.electrode coupledfto atvoltage divider comprising a resistor 48zand 'aresistorl 53 having a parallel-connectedrhigh-frequency by-pass condenser MpoupIedfbetween arsource ;B"'fand" the output circuit oi unit l1. Thezanodecf thei tube il] is connected to the junction of the resistors 33 and '35 andthe.` cathode thereof isfdirectly connected to the ksource '-B.

Thefautomatic potential-control"systemT22 also includes a circuit, coupled between the 4given point 281and Athe rstcircuit means comprising the tube-'29, responsive'to deviations of the potential at the givenr pointfrom theabove-mentioned predeterminedfvalue during-the intervening intervals for'controllingthe impedance of the first circuit means to maintain the potential at'fthe given .point "at therpredetermined' value during 'theintervening intervals. "Moreparticularly,"this vcircuit comprises avfeed-fback circuit including `an electron-discharge* amplier tube "4S having a cathodeicoupled to the source B through arre- -sistor llt, aI control electrode coupled to the given `point 28 and 'an lanode coupled to the first circuit means, specii'ically,1tothe control electrode of the tube 2Q throughresistorstl and33 for applying thereto deviations of the potential at the vgiven point 28rfrornv the-predetermined kvalue during the intervening:intervals: for controlling .the impedance of the tube 29 relativeto the impedance oxthe tube -38 and the resistor '39. The gating gcircui.t...tubei144.is coupled tothe feed-back icircuit,1in particularv to'ithe: :cathode of f the tube 4S, for applyingztheretof repetitivegatingspulses 7 for preventing control-electrode current flow in the tube 49 during the gating intervals.

A tube U also included in the unit 22 has an anode connected to the source +B, a cathode coupled through the resistor 46 to the source B, and a control electrode coupled to an adjustable voltage divider 5l which is coupled through a resistor 52 between the source -B and ground for controlling the predetermined value of the potential at the point 28 during the intervening intervals, as will be explained more fully subsequently.

Operation. of Fig. 1 automatic potential control system The operation of the automatic potential-control system of Fig. 1 may best be understood by referring to Fig. 2 of the drawings which is a graph representing the potential-time characteristics of the output signals of the various units of Fig. l radar system. Curve A of Fig. 2 repre sents the output signal of the unit il which comprises repetitive positive pulses and is applied as a gating signal to the control electrodes of tubes 40, 44 and 4'! of the potential-control system 22. Assume for the moment that prior to a time to the tubes 49, 44 and 4l have been nonconductive and that the tubes 3S, 3S, 29, 49 and 59 have been conductive. The first positive gating pulse then occurs during a time interval to-tz to render conductive the tubes 49, 44 and 4l. Current flow from the source +B through the tube 4.' and the resistors 39 and 42 to the source +B raises the potential at the junction of the resistors 39 and 42 sufficiently to render nonconductive the diode 38. Similarly, current flow from the source +B through the tube 44 and the resistor 46 to the source -B raises the potential at the cathodes of the tubes 49 and 5l) suiciently to prevent cona trol-electrode current now in the tube 49 during the interval tri-t2. Further, current flow from the source +B through the resistor 35 and the tube lil' to the source +B lowers to a negative value the potential at the junction of the resistors 33 and 35 and, hence, lowers the potential at the control electrode of the tube 29. This decrease in potential increases the impedance of the tube 29 relative to the resistance of the resistor 3'? and renders the diode 36 nonconductive because of the negative potential then applied to the anode of the diode through the resistor 5! from the source -B. Since the diodes 36 and 38 and control electrode of the tube 49 are nonconductive during the gating interval tri-t2, the point 28 is isolated from the sources -B and +B during that interval. Also, the operation of the tube 4l renders the tube 49 nonconductive during the interval t-tz.

During the gating intervals, the sweep ampliner 25 applies to the sweep amplifier 23 through the condenser 2l repetitive saw-tooth pulses, having, for example, polarity and magnitude as represented by curve B, the first of which sweeps from a negative to a positive potential during a time interval ta-t1. Although the condenser 2i is a large coupling condenser, that condenser charges somewhat through the input impedance of the sweep amplier 23 during the sweep time of the signal represented by curve B. Accordingly, assuming for the moment that the potential at the point 29 is zero at the time tu, curve C then represents the signal developed at the point 28. Note from curve C that due to the incremental charge developed on the condenser 2l during the sweep time, the signal developed at the point 28 has a somewhat dlstortedpo's'itive peak. Accordingly, during the time interval ti-tz, when the signal represented by curve B falls to its initial negative potential, the signal developed at the point 28 falls below zero potential, as represented by curve C, by an amount equal to the difference in the peak positive amplitudes of the signals represented by curves B and C.

Since the condenser 2| also acquires incremental charges during the application of successive saw-tooth pulses thereto, in the absence of the unit 22 these incremental charges would become cumulative and result in an instability in the operation of the sweep amplifier 23 and in the Adisplay on the cathode-ray tube screen of the plan-position indicator I6.

To avoid such instability, during the intervals intervening the gating intervals, for example, during the interval tz-tz, the potential-control system 22 automatically maintains the potential at the point 28 at a predetermined value, for instance, zero potential. At the time t2 the rst gating pulse of curve A terminates, rendering the tubes 48, 44 and 4l nonconductive during the interval t2-t3. Accordingly, the potential at the junction of the resistors 33 and 35 rises due to the cessation of current iiow through the tube 4l, and the potential at the cathode of the tube 49 drops due to cessation of current iiow through the tube 44. The tube 49 then conducts, but as tube 41 is made non-conductive, a resultant decrease in current now through the resistor 35 occurs so that the potential at the anode of the tube 49 rises from a negative to a positive value, as represented by curve D of Fig. 2. Accordingly, the potential at the control electrode of the tube 29 rises causing that tube to become more conductive. Current ow from the source +B through the tube 29 and the resistor 3l to the source -B causes the potential at the anode of the tube 36 to rise sufficiently to render that tube conductive.

During the interval t2-t3, the discontinuance of current now from the source +B through the tube 48 and the resistors 42 and 39 to the source -B causes the potential at the cathode of the diode 38 to fall below the anode potential thereof, thus causing tube 39 to conduct. The discharge current from the condenser 43 through the resisters 42 and 39 causes a slight delay in the fall of the potential at the cathode of the tube 38 to allow current flow from the source +B through the tubes 29 and 35 to the point 2S and the condenser 2| slightly before the tube 3B is rendered conductive. Current then flows during the interval tz-ta from the source +B through tubes 29, 36 and 38 and the resistor 39 to the source -B and also through the tube 29 and the resistor 31 to the source +B.

Since the potential at the point 28 and the control electrode of the tube 49 is negative at the time t2, as represented by curve C, and, hence, below the assumed predetermined value of Zero potential, the anode potential of the tube 49 is higher than the quiescent value thereof when the potential at the point 28 is zero during the intervals intervening the gating intervals. Accordingly, at the time t2, the potential at the' control electrode of the tube 29 is higher than the quiescent value thereof during the intervening intervals and, hence, the impedance of the tube 29 is less than its quiescent value during the intervening intervals. Thus, because of the reduced impedance of the tube 29 relative to the required for the potential at the point 28 to rise 5 from a negative to `Zero potential is determined. by the timefconstant of the/condenser 2l and. theoutput imp'edance'oi theunit 22'. Thevunit 22 has avery low output impedance beeauseof;

the feed-back circuit which applies a degenerarev` 10-3' tive feed-back signal through the amplier 494:0: the control-electrode of the tube 29.rv

From the foregoing explanationof the-operas tion of the automaticpotential-control system 22;"

variable impedancetube 29 to alter 'the'iinpede'v 20 ance thereof and thuszto cause the-"potential-at: thezpointl rapidly toreturnzto:thecpredeters mined value. Accordingly,` a sharp-positive peak:y app-earsk in the; signal. developed at the' anode f. ofi;

atingconditionsfiwhieh cause. the potentialA at?. 30

thespointrto-rise above thepredetermined value.- during the intervals.; intervening. the.. gating.. ingr( tervals; the: feedf-loa'ck .circuit .functionszin :a marrer ner. similar to .that justsdescribed` and causes. the? 29 to: be'rnoi'einegative than itsfquiescent 'value1 during. the; intervening? intervals, thus i increasef irigthe: impedance: of fthe;` tube 29. relative: to the;y impedance; ofH the. resistor' 39.'.and causing. the? potentiaiat `me point- 28 rapidly to fau.: to the@ 40 predetermined; value` thereof.

The; predetermined.; value ofx ,the a potentialiatz the point'zZ 3 during `the;intervening-zintervals .mayr be controlled' by. adjustment of: tlfie'..voltage vider; 5l which: determines. thea. controleelectrodei A potential'. of.; the '.tubef' 5d; A'change'in' the troleelectrode potential. oiithettube changes' the. cathodef-Lpotential of theftube'i 49; causing? theiranode potential of; that*l tuloeil to: changes an'dz thus altering theimpedencesoithe tube 29.. The: 50

change. in .ther impedance: ofi tiret/tube." v2.91 results in; the; determination` of aI newg predeterminedi value1for-the potentialat the-fpoint. 28 during." the intervening intervals;

While-applicant does'not wish to be lirnitedto:l any.l particular" circuit. constants, the: follow-ing have: beenk employed ;in a; potential-control.-v sys-.f tem constructedin accordancev'with Figrlzzl@ Resistorv 53; 270 Vkilohrns Tube 29 1,/2 section oi Type 12A'I7 Tube. 36 1/2 section of'Type 6AL5 Tube 38 1X2 section oi Type6AL5 Tube 40 V2 section of Type 12AU7 Tube. 44 lgrsection of.'Iype.12AU7 Tube'.47 1/2 section of Type TZAT? Tubez49; 1/2 section of Type 5691 Tube 5.O ..1/2 sectiono Type 5691 Source: -|-B l. +226 volts Source.- -B -180 volts Source. .-B. 350. voltsA Fromthelforegoing description it Will be apit will be understood that during the intervals: 152?param;thatanautomatlc potenmalncontrcl Systern constructed-iin accordance Ywith the invention has the advantage of isolating a point in the system from a potential-supply circuit during predetermined gating intervals and of providing a low output` impedance for automaticallyY maintaining-the potential at that point at a predetermined value during intervalsl intervening-"the gating intervals;

Wlrile-thereahas; been described what is at the tube 4%- represented by' Acurve DA as a result.. 251 present consderedtdbe the preferred" embod" ment-of this invention, it will be obvious to' those skilled inthe art tliat'various changes and modiideati-'onsL may be made therein Without departing-from--fthe invention,Y and'it is, therefore; aimed to coverV all such changes' and' moolications4 as fall-Within theitruespiritandv scope of the invention;

What is claimed is:

l. In gated systernf'having' one operating phase during" predeterminedfgating intervals'and, potential atztheacontroli electrode.- of ther tube: 3D1

another operatingphaseduring. trie intervening intervals; control system-` for-f automatically maintainingthe potential-at a given point in the gated system-'at'af-predetermined .value during the interven intervals comprising: a source ofy unidirectional* potentiali a two-partr voltage divider" coupled inA a seriesk relation With` said source, said given point beingi intermediate said twov parts, onepart` including a rstelectron tube off variable viinpedeuoce for controlling current nowftherethrouglrlandf'a diode coupled in a series relation with" said. electron: tube betweenysaid sourceiand saidfgiven point:;witn1atpredetermined polarityfiorf interrupting currentglow through said onetpartfnand: the other.` part `including 'an eleinentrzof;substantiafli impedance and a diode coupled `loetvveerrsaidsourceandi said given point with the. sameLpolarity inzafseries relationvwithr said substantiat impedance'elementorrinterrupting currentow therethrough; a gating cireuitfor applying.totsaidodiodeszrepetitive, gating potential pulsesf for: rendering: saidr diodes," nonconductive to isolate:-saidgivempoint from said source during said.. gating: intervals; L' and a: feed-baci:I circuit; comprising? an; amplifier having; aA control electrode coupled to.v said-'a given point and an anodeeoupled..toY said-:mst yelectron tube for applyingthereto; dei/.iationsrof the*- potential lat said pointrorn said 'predetermined val-uezduring said intemzeni-ngf.V interi/,als 'to control vthe impedance of:.;'said'1firstrelectronfftube relativeV to the iin-- pedance of said substantial impedance `element and: toemaintairrf'said potential; at. said predeterminedvalues duringfisaidx intervening interfvalsi'gsaid gating?.- ci1-'cuit"also beingf coupled:` to said feed-"backI .circuit fori'. applyingfthereto repetitiveigatirrg r pulses .Iforrendering saidv feed".-l

backzf circuiti Iinoperative--.v during said4 gatingxin tervals:-=

2.2;In; aeg-a'tedeesystem'i having one: operating phasedringpredetermined gatingsintervals and another operating phase during the intervening intervals, a control system for automatically maintaining the potential at a given point in the gated system at a predetermined value during the intervening intervals comprising: a potential-supply circuit; a two-part voltage divider coupled in a series relation with said potentialsupply circuit, one part including potential-responsive iirst circuit means of variable impedance for controlling current flow therethrough and the other part including a second circuit means of substantial impedance; potential-responsive third circuit means coupled between said potential-supply circuit and said given point; a circuit for applying to said third circuit means repetitive gating potential pulses for rendering the same nonconductive; means including said third circuit means for isolating said given point from said supply circuit within the control system during said gating intervals; and a circuit coupled between said given point and said rst circuit means and responsive to deviations of the potential at said point from said predetermined value during said intervening intervals for applying to said iirst circuit means a control potential variable in magnitude during said intervening intervals and determined during said intervening intervals by said potential at said given point for controlling the impedance of said first circuit means to maintain said potential at said given point at said predetermined value during said intervening intervals.

3. In a gated system having one operating phase during predetermined gating intervals and another operating phase during the intervening intervals, a control system for automatically maintaining the potential at a given point in the gated system at a predetermined value during the intervening intervals comprising: a source of unidirectional potential; a two-part voltage divider coupled in a series relation with said source, one part including potential-responsive iirst circuit means of variable impedance for controlling current flow therethrough and the other part including a second circuit means of subtantial impedance; potential-responsive third circuit means coupled between said source and said given point; a circuit for applying to said third circuit means repetitive gating potential pulses for rendering the same nonconductive; means including said third circuit means for isolating said given point from said source within the control system during said gating intervals; and a circuit coupled between said given point and said first circuit means and responsive to deviations of the potential at said point from said predetermined value during said intervening intervals for applying to said first circuit means a control potential variable in magnitude during said intervening intervals and determined during said intervening intervals by said potential at said given point for controlling the impedance of said irst circuit means to maintain said potential at said given point at said predetermined value during said intervening intervals.

4. In a gated system having one operating phase during predetermined gating intervals and another operating phase during the intervening intervals, a control system for automatically maintaining the potential at a given point in the gated system at a predetermined value during the intervening intervals comprising: a potentialsupply circuit; a two-part voltage divider coupled in a series relation with said potential-supply circuit, one part including potential-responsivev rst circuit means comprising an electron-discharge device of variable impedance for controlling current flow therethrough and the other part including a second circuit means of substantial impedance; potential-responsive third circuit means coupled between said potentialsupply circuit and said given point; a circuit for applying to said third circuit means repetitive gating potential pulses for rendering the same nonconductive; means including said third circuit means for isolating said given point from said supply circuit within the control system during said gating intervals; and a circuit coupled between said given point and said electron-discharge device and responsive to deviations of the potential at said point from said predetermined value during said intervening intervals for applying to said electron-discharge device a control potential variable in magnitude during said intervening intervals and determined during said intervening intervals by said potential at said given point for controlling-the impedance of said electron-discharge device to maintain said potential at said given point at said predetermined value during said intervening intervals.

5. In a gated system having one operating phase during predetermined gating intervals and another operating phase during the intervening intervals, a control system for automatically maintaining the potential at a given point in the gated system at a predetermined value during the intervening intervals comprising: a potential-supply circuit; a two-part voltage divider coupled in a series relation with said potentialsupply circuit, one part including a iirst electron-discharge device of variable impedance and a second electron-discharge device coupled in a series relation therewith for interrupting current flow through said one part and the other part including circuit means of substantial impedance and including potential-responsive circuit means coupled between said potential-supply circuit and said given point; a circuit for applying to said second electron-discharge device and to said potential-responsive circuit means repetitive gating potential pulses for rendering said second electron-discharge device and said potential-responsive circuit means nonconductive; means ineluding said second electron-discharge device and said potential-responsive circuit means for isolating said given point from said supply circuit within the control system during said gating intervals; and a circuit coupled between said given point and said rst electron-discharge device and responsive to deviations of the potential at said point from said predetermined value during said intervening intervals for applying to said first electron-discharge device a control potential variable in magnitude during said intervening intervals and determined during said intervening intervals by said potential at said given point for controlling the impedance of said iii-st electron-discharge device to maintain said potential at said given point at said predetermined value during said intervening intervals.

6. In a gated system having one operating phase during predetermined gating intervals and another operating phase during the intervening intervals, a control system for automatically maintaining the potential at a given point in the gated system ata predetermined value during the intervening intervals comprising: a potential-supply circuit; a two-part voltage divider coupled in a series relation with saidpotentialagregar-et sponsive circuit means repetitive gating* poten tial-pulses iorrendering saiddiodef andfsaid potential-responsive* circuit means noncenductive;A

means 4including said diod'efandl said potential# responsive circuit Y means for isolating said giveni point'from saidsupply circuitiwitliin thecontrol system during saidfgating intervals; and'fav cii-''-- cuit rcoupled between said' givenpointY and said electron ftubeanzt-responsiveitol deviationseof-ftiie' potential at point'ffrom said' predetermined valuee during said intervening-iintervalsk for -applying V-`to said electron* tube =a control *potential variable -in' magnitudef-during saidintervening` intervals vand 'determinedduringisaid intervening intervalsu byl said potential-at said-given point' for-controlling the/impedancer ofl said electron' tube'to maintain' said potential at said given pointJ at salda-predetermined-valueduring-.said intervening intervals;

'7'. In a gated*systemi'havingf one operating phase Iduring 'predetermined gating 'intervals and another operatingphase during the intervening intervals, a control system for automatically maintaining-the potential at' a given point in the gated Y system'- at' a" predeterminedy value during the* intervening'l'intervals comprising: apo-iA tential-supply" circuit; 1 a two-part voltage divider'Y coupled Yin al series 'relation' with said f potential# supplyl circuit,- said 'Y given point `being interrnee diate said two parts, one part includingpoten tial-responsive circuit means of variable impedance for controllingcurrent ow therethrough and the other part including'anelement of substantial impedance and afseries-connected uni-I directionally lconductive devicecoupled .between said potential-supply circuitzand. said given point for interrupting current flow through said other part; device repetitive gating potential pulses for rendering the same nonconductive; means including said device for isolating said given point from said supply circuit within the control system during said gating intervals; and a circuit coupled between said given point and said circuit means and responsive to deviations of the potential at said point from said predetermined value during said intervening intervals for applying to said circuit means a control potential variable in magnitude during said intervening intervals and determined during said intervening intervals by said potential at said given point for controlling the impedance of said circuit means relative to the impedance of said substantial impedance element to maintain said potential at said given point at said predetermined value during said intervening intervals.

8. In a gated system having one operating phase during predetermined gating intervals and another operating phase during the intervening intervals, a control system for automatically maintaining the potential at a given point in the gated system at a predetermined value during the intervening intervals comprising: a potentialsupply circuit; a two-part voltage divider coupled in a series relation with said potential-supply circuit, said given point being intermediate said ld" twov par-tail oneflpart'f including f p'otential'respon f siveirst circuit means of'variable-impedanceandi a diode coupled-between saidsupplycircuitrandff' said given point with a=predetermined polarityfor interrupting current ow; therethrough! and the other part includingj a second. circuit.i means-otr substantial impedance and adiode coupled-Tha`r tween said supplyl circuit and? saidl givent point Y witlrtheffsan'ien polarity-"for interrupting currenty iiowV therethrough 1,' a-v cineuit-for` applying to *said* twofdiodesirepetitive gatingfpotential pulses for: renderingJ the same'non'conductive; means-'ini1v cluding-said diodes for isolatingsaid given point from said supply:circuitA within the'control` sys' tem during said" gatingintervals; and av circuit coupled between saidgivenfpoint and saidii'rstf circuit means and' responsive to deviations v offtle potential atsaid point-from said predetermineali value during'said interveningintervalsfor appl-ye ing 'to' said rst circuit means a controlpoten-'f tia-l' variable in magnitude lduring said intervenen ingv intervals and determined during said inter-- vening intervals by said potential-atsaid-#givenl point#for'fcontrolling thefimpedanceof said -'rst circuitv means'to' maintain said potential at said given'point at saidI predetermined value during said intervening intervals'.

9. Inv a gated systemV having one operatingvv phase during predetermined gating intervalsand another operating phasel during-the-intervening intervals, a control system forf'automaticaHy" maintaining thev potential at a givenr 'point-r in` the gated system at a predetermined valueduring the intervening intervals comprising: a potential-supply circuit; a two-part voltagey divider coupled in a seriesrelation with'said potentialsupply circuit, one part including potentialresponsive first circuit means of' variable inrpedance for controlling-currentinow therethrough and the otherpartl including-a secondy circuit means of substantiall impedance;V potential-'- responsive third circuit meansI coupled between said potentialesupplycircuit and' said givenpoint; a gating 'circuit'for applying lto said third circuit means repetitive gating potential pulsesv for rendering the same nonconductive; means in'-A cluding said third-circuit means-'for isolating-said given lpointfrom"said'*supply'circuit within the control system during said gating intervals; and a feed-back circuit coupled between said given point and said first circuit means and responsive to deviations of the potential at said point from said predetermined value during said intervening intervals for applying to said first circuit means a control potential variable in magnitude during said intervening intervals and determined during said intervening intervals by said potential at said given point for controlling the impedance of said irst circuit means to maintain said potential at said given point at said predetermined value during said intervening intervals, said gating circuit also being coupled to said feed-back circuit for applying thereto repetitive gating pulses for rendering said feed-back circuit inoperative during said gating intervals.

10. In a gated system having one operating phase during predetermined gating intervals and another operating phase during the intervening intervals, a control system for automatically maintaining the potential at a given point in the gated system at a predetermined value during the intervening intervals comprising: a potentialsupply circuit; a two-part voltage divider coupled in a series relation with said potential-supply circuit, one part including potential-responsive iirst circuit means of variable impedance for controlling current now therethrough and the other part including a second circuit means of substantial impedance; potential-responsive third circuit means coupled between said potentialsupply circuit and said given point; a circuit for applying to said third circuit means repetitive gating potential pulses for rendering the same nonconductive; means including said third circuit means for isolating said given point from said supply circuit Within the control system during said gating intervals; and a feed-back circuit comprising an electron-discharge amplifier tube having a cathode coupled to said po` tential-supply circuit, a control electrode coupled to said given point and an anode coupled to said rst circuit means for applying thereto deviations of the potential at said point from said predetermined value during said intervening intervals to control the impedance of said iirst circuit means and to maintain said potential at said given point at said predetermined value during said intervening intervals.

11. In a gated system having one operating phase during predetermined gating intervals and another operating phase during the intervening intervals, a control system for automatically maintaining the potential at a given point in the gated system at a predetermined value during the intervening intervals comprising: a potentialsupply circuit; a two-part voltage divider coupled in a series relation with said potentiabsupply circuit, said given point being intermediate said two parts, one part including potential-responsive first circuit means of variable impedance for controlling current iioW therethrough and the other part including a second circuit means of substantial impedance; potential-responsive third circuit means included in said voltage divider and coupled between said potentialsupply circuit and said given point; a circuit for applying to said third circuit means repetitive gating potential pulses for rendering the same nonconductive; means including said third circuit means or isolating said given point from said supply circuit Within the control system during said gating intervals; and a circuit coupled between said given point and said first cir- 116 cuit means andresponsive-to `deviations of the potential at said point from said predetermined value during said intervening intervals for applying to said first circuit means a control potential variable in magnitude during said intervening intervals and determined during said in tervening intervals by said potential at said given point for controlling the impedance of said rst circuit means to maintain said potential at said given point at said predetermined value during said intervening intervals.

12. In a gated system having one operating phase during predetermined gating intervals and another operating phase during the intervening intervals, a control system for automatically maintaining the potential at a given point in the gated system at a predetermined value during the intervening intervals comprising: a signalresponsive potential-supply circuit having a controllable potential-current ow characteristic; signal-responsive circuit means coupled in circuit With said supply circuit and said given point; a circuit for supplying to said circuit means repetitive gating pulses for rendering the same nonconductive; means including said circuit means or isolating said given point from said potential supply circuit within the control system during said gating intervals; and a circuit coupled to said given point and said supply circuit and responsive to deviations of the potential at said point from said predetermined value during said intervening intervals for applying to said potentialwsupply circuit a control signal variable in magnitude during said intervening intervals and determined during said intervening intervals by said potential at Said given point for controlling said characteristic of said potential supply circuit to maintain said potential at said given point at said predetermined value during said intervening intervals.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 2,491,029 Brunn Dec. 13, 1949 2,577,536 MacNichol Dec. 4, 1951 

